The towering black hat, or busby, dates back almost 200 years to the Battle of Waterloo and is a key part of the uniform of the five guards' regiments - the Coldstream, Grenadier, Irish, Scots and Welsh.

I was slightly startled to find myself walking a few paces behind a Guardsman in full Number 1 dress uniform, busby standing proud, and polished brass spurs on his boots.